I think this was well-written and clear, so good job there! I also happen to disagree with the contents.
First off, I’m highly suspicious of any definition of a “prevailing conception” of physics that excludes the second law of thermodynamics! It seems like in actual practice, sometimes people make predictions by simulation, (the “PC”) sometimes they make predictions by generalizing about the character of physical law (the quantum gravity example), and sometimes they do something in between those things and make abstractions/generalizations but then treat those abstractions as tools to do simulation (condensed matter theorists I see you).
And so what does it mean to recast physics in a different picture? Does this mean people are going to be rendered unable to do simple simulations about what actually happens when you shoot a particle at a barrier? No, that would be madness—you either give people the tools to do such calculations, or you get laughed out of the room.
So then does it mean that we’re going to be able to make new exciting arguments that physicists were unable to make before? I mean, I’d love it if this were true, but I’m skeptical. My cynical side expects that there will be few new sorts of arguments, but plenty of flag-planting on old sorts of arguments.
I think this was well-written and clear, so good job there! I also happen to disagree with the contents.
Thanks for your comment!
First off, I’m highly suspicious of any definition of a “prevailing conception” of physics that excludes the second law of thermodynamics! It seems like in actual practice, sometimes people make predictions by simulation, (the “PC”) sometimes they make predictions by generalizing about the character of physical law (the quantum gravity example), and sometimes they do something in between those things and make abstractions/generalizations but then treat those abstractions as tools to do simulation (condensed matter theorists I see you).
Yeah, the term ‘prevailing conception’ is Deutsch’s. It refers specifically to formulating things in terms of initial conditions and dynamical law. I agree its not a great term, as it implies that all current physics comes under its umbrella, which, as you pointed out, is not true.
And so what does it mean to recast physics in a different picture? Does this mean people are going to be rendered unable to do simple simulations about what actually happens when you shoot a particle at a barrier?
The idea isn’t to throw away the dynamical laws picture, but to provide a different angle of attack on some problems that seem intractable when expressed in the PC.
So then does it mean that we’re going to be able to make new exciting arguments that physicists were unable to make before?
That’s the hope!
I mean, I’d love it if this were true, but I’m skeptical. My cynical side expects that there will be few new sorts of arguments, but plenty of flag-planting on old sorts of arguments.
Fair enough. I’m skeptical as well. Constructor theory has produced a couple of interesting results, but as far as I can see, nothing world-changing yet. But I am still convinced that the problems described here (eg. the incompatibility of reversible dynamics with irreversibility of the 2nd law) are real problems. Even if counterfactuals/constructor theory don’t work (who knows?), we will need something new to address them!
I think this was well-written and clear, so good job there! I also happen to disagree with the contents.
First off, I’m highly suspicious of any definition of a “prevailing conception” of physics that excludes the second law of thermodynamics! It seems like in actual practice, sometimes people make predictions by simulation, (the “PC”) sometimes they make predictions by generalizing about the character of physical law (the quantum gravity example), and sometimes they do something in between those things and make abstractions/generalizations but then treat those abstractions as tools to do simulation (condensed matter theorists I see you).
And so what does it mean to recast physics in a different picture? Does this mean people are going to be rendered unable to do simple simulations about what actually happens when you shoot a particle at a barrier? No, that would be madness—you either give people the tools to do such calculations, or you get laughed out of the room.
So then does it mean that we’re going to be able to make new exciting arguments that physicists were unable to make before? I mean, I’d love it if this were true, but I’m skeptical. My cynical side expects that there will be few new sorts of arguments, but plenty of flag-planting on old sorts of arguments.
Thanks for your comment!
Yeah, the term ‘prevailing conception’ is Deutsch’s. It refers specifically to formulating things in terms of initial conditions and dynamical law. I agree its not a great term, as it implies that all current physics comes under its umbrella, which, as you pointed out, is not true.
The idea isn’t to throw away the dynamical laws picture, but to provide a different angle of attack on some problems that seem intractable when expressed in the PC.
That’s the hope!
Fair enough. I’m skeptical as well. Constructor theory has produced a couple of interesting results, but as far as I can see, nothing world-changing yet. But I am still convinced that the problems described here (eg. the incompatibility of reversible dynamics with irreversibility of the 2nd law) are real problems. Even if counterfactuals/constructor theory don’t work (who knows?), we will need something new to address them!